/**
 * It provides submarine class that occupies three grid squares.
 * 
 * @correspondence submarine is one of the valid type of ship that can be placed.
 * @convention Provide the name and length of submarine type of ship.
 * 
 * @author vo, wu and wyan
 */
public final class Submarine extends Ship {

	/**
	 * Submarine constructor. 
	 * @ensure ship is submarine with the length of three grid squares.
	 */
	public Submarine() {
		super("Submarine", 3);
	}

}
